Station identification for party lines



Oct. 1952 L. B. MITCHELL STATION IDENTIFICATION FOR PARTY LINES Filed Dec. 10, 1949 J Ev J 1% jail? INVENTOR. LEN B. MITCHELL ATTORNEY Patented Oct. 21, 1952 STATION IDENTIFICATION FOR PARTY LINES Len B.'Mitchell, Wheaton, Ill., assignor to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application December 10, 1949, Serial No. 132,240

This invention relates in general to automatic telephone systems and more particularly to an apparatus and circuit whereby the calling subscriber on a multi-party telephone line may be identified.

It is an object of this invention to provide a simple and effective system for identifying the calling subscriber on a multi-party line.

Another object is to provide a party line identification system which may be readily utilized in automatic call recording systems.

A further object is to provide a party line iden" tiiication system in which a plurality of voltage divider networks associated with subscribers sets are adjusted to control the current passing through an indicating circuit so that a controlled voltage passing through one of the divider'networks will act upon it to operate the indicating circuit.

Other objects of the invention will be apparent from the following specification taken in connection with the accompanying drawing.

Referring generally to the drawing, a plurality of subscribers sets are shown at In, H, l2, and it. These sets are connected in common to the lines l4 and I5. The subscribers set Ill may be standard in every respect. However, each of the sets it, l2, and It contains a voltage divider network. V

Each voltage divider network consists of a resistance ll connected in parallel with a nonlinear element such as a neon tube 18. With this parallel hookup when a low potential is applied across the resistance the neon tube is not conducting. As the potential across the resistance ll isincreased, a point is reached at which the neon tube I3 conducts and this serves as an effective short circuit for a part of resistance I! and almost none of the current will pass through the part of resistance .11 which is short circuited.

The several resistance-neon tube combinations may be adjusted so that at a particular voltage one neon tube will begin to conduct; at a higher potential an additional neon tube may be adjusted for conductance; and at a still higher potential an additional neon tube may be adjusted for. conductance. Thus, it is possible to adjust the resistance-neon tube combinations so that each step-wise increase in voltage will enable an additional neon tube to conduct provided the subscriber has removed his receiver from the hook to place the network including the particular tube in the circuit. I

This principle is utilized in the present invention to indicate which subscriber on a partyline 11 Claims. (01. 179-17) is using his telephone. The system is well suited for use in connection with an automatic call recording equipment.

Lines i l and it are shown passing through a line finder is, primary selector 2i and a director hunter 22. These pieces of equipment are shown in block form since they are standard in every respect.

For the purpose of this invention the line finder l9 and the primary selector 25 may be of the wellknown type of Strowger switch having vertical and rotary motions, while the director hunter 22, which is connected to the primary selector, may be of the well-known rotary type for selecting an idle identification apparatus. However, this invention is intended for use in toll ticketing systems of the type shown in the Ostline Patents 2,352,492, 2,409,063 and 2,385,228, issued June 27, 1944, October 8, 1946, and September 18, 1945, respectively, wherein switches of the type above dc scribed are employed.

The battery ill may be used to supply varying voltage potentials, e. g., 100, 133, 269 volts, through the divider networks it by means of a series of taps d6, ll, and .8 which may be cut into the network circuit under the control of con tacts of a group of serially operating relays 58, 6d, 10, and 8%. These serially operated relays set up a test cycle and prepare operating circuits for a series of registering relays fill, Hit, and Mil A marking relay 35 is located in the network circuit. This marking relay 3-5 is sensitive to the current flow thru it so that when one of the neon lamps begins to conduct marking relay will be operated to complete a circuit to one of the registering relays ilil, ltd, and 5 iii.

The operation of registering relays sales, and ill} in turn controls the operation of a series of recording relays its, lit, lit, and tilt. As'shown on the drawing, these recording relays control the operation of a series of signal lamps I42, and E52. In an automatic recording system these signal lamps would be replaced by auto matic recording apparatus.

An overload relay 323 may be providedin order to prevent false operation and also to pr vide a warning signal such as a bell A relay which responds to the operation of overload r ay 38 may be utilized to route calls to a board (not shown) when the overload relay is operated. g

The operation of the apparatus will now be described in detail. Let it be assumed that the resistance-neon tube combination at subscribefs station H is adjusted so thatthe neon tube becomes conducting at an applied potential of 100 volts; at the subscribers station I2 the parts are adjusted so that the neon tube responds to an applied potential of 133 volts; and at the subscribers station I3 the parts are adjusted for operation of the neon tube shown upon an applied potential of 200 volts.

Let us now assume that the subscriber at station I3 lifts his receiver and operates the switchhook. Ground is now furnished through contacts 53, the subscribers set, and contacts 55 for energization of the lower winding of line relay 30. Line relay then locks up over its upper winding through contacts 81 and 3 I.

At its contacts 32, line relay 30 furnishes ground for the operation of slow release relay 40. Relay operates and at its contacts 42 furnishes ground for the operation of slow release relay 50. At its contacts 4| relay 40 prepares locking ground for registering relays 90, I00, and I I0.

When relay is energized it furnishes ground through its contacts 5! for the operation of relay 60 which is slow to operate. At its contacts 54 it prepares a circuit connecting marking relay 35 through the voltage divider networks It and opens its contacts 55 to break the circuit to the lower winding of line relay 30. At its X contacts 56 it provides another locking circuit for relay 30.

When relay 60 is energized it closes its contacts BI to provide ground for the operation of relay I0 which is slow to operate. At its contacts 62 it prepares a circuit for the operation of relay 90. At its contacts 63 it closes the following circuit for impressing a 100 volt potential upon the divider network I6 at subscribers station I3; ground, a 100-volt portion of battery 45, tap 46, contacts 63, contacts 15, contacts 88, relay 38, marking relay 35, contacts 54, switch train 22, 2| and I9, network I6 at station I3, and ground. This 100-volt potential is not suflicient to operate the neon tube I8 at subscribers station l3. Since the neon tube did not conduct, relay 35 was not operated and registering relay 90 was likewise not operated.

When relay I0 operates an instant after relay 50, it opens its contacts I3 and closes its contacts I2 to break the operating circuit for relay 90 and prepare an operating circuit for relay I 00. It opens its contacts I5 to break the 100-volt circuit through battery 45 and tap 46 and closes contacts I4 to complete a 133-volt circuit through tap 41 of battery 45 and mark relay 35 to the voltage divider network IE. Since a 133-volt potential is not sufiicient to operate the neon lamp I8 at subscribers station I3 the marking relay 35 is not operated.

When relay I0 operated it closed its contacts II to furnish ground for the operation of relay 80 which is also a slow-to-operate relay. Upon the operation of relay 80 an instant after relay I0 operates, contacts 84 are opened to break the circuit previously prepared for the operation of relay I00 and contacts 86 are closed to prepare a circuit for the operation of relay I I0. Contacts 81 are opened to break one locking circuit for line relay 30 which nevertheless remains operated because of ground furnished through X contacts 55. Contacts 88 open to break the 133-volt circuit and contacts 89 close to complete a 200-volt circuit through marking relay 35 and voltage divider network I6 over tap 48. Contacts 8I complete a locking circuit to grounded contact 42.

Since the resistance I! and neon tube I8 at station I3 have previously been adjusted to enable 4 the neon tube I8 to conduct at the 200-volt level, marking relay 35 will now be operated when the neon tube I8 at station I3 conducts.

The operation of marking relay 35 closes its contacts 36 which completes the following circuit for the operation of relay H0; ground, contacts 36, 85, 83, I02, relay H0, and battery to ground. Relay H0 operates andcompletes a locking circuit for itself through contacts M and III. At its contacts H2 it prepares a circuit for the operation of indicating relay I50. At the time relay operated it opened its contacts 82 to break the operating circuit of slow-release relay 50 which held operated for a short interval. At its contacts 81 it broke one of the locking circuits of line relay 30. Immediately upon the release of relay 50 the following circuit Was completed for the operation of indicatin relay I50: ground, contacts '42, 83, 52, 95, I04, II2, relay I50, and battery to ground.

The release of relay 50 closes its contacts 53 and 54 before opening its X contacts 56 to reestablish the loop circuit over the switch train for line relay 30. Line relay 30 is therefore maintained over the calling loop to hold relay 40 operated.

The operation of relay I50 closed its contacts I5I to complete an operating circuit for the indicator lamp I52. This lamp I52 provided visual evidence that station I3 initiated the call. An automatic means for recording the call could have been operated through contacts I5I as well as the lamp I52.

Assuming the voltage divider network I6 at station I2 had been adjusted to enable the neon tube l8 to conduct at 133 volts and further assuming that the call was initiated at this station rather than station I3 the course of operations would have been the same as that indicated above for station I3 except that the marking relay 35 would have been energized at the time the neon lamp at station I2 short circuited the part of the 133-volt current taken off battery 45 through lead 41 which passed through that portion of resistance II in parallel with neon tube I8. The operation of marking relay 35 would have completed a circuit through contacts 36, 84, I2, and 92 for the operation of registering relay I00. Registering relay I 00 would have looked through contacts 4| and IM and would have opened its contacts I 02 to disable the operation of registering relay H0. Thus, when relay 80 would subsequently introduce the ZOO-volt potential from battery 45 through tap 48 the neon tube at station l2 would again be operated and marking relay 35 would again be energized but registering relay I I0 would not be operated since the previous operation of relay I00 had disabled it at the contacts I 02.

The operation of relay I00 would complete a circuit for the operation of recording relay I40 in a manner comparable to that previously described for the operation of relay I50 and lamp I42 would be operated to indicate that a call had originated at station I2.

If the call had originated at station I I the neon tube therein would have become conducting at the time relay 60 introduced a 100-volt potential through tap 46. Marking relay 35 would have been energized to complete an operating circuit for registering relay 90 through contacts 36, 84, I3, and 62. Relay 90 would have locked up through contacts 4| and 9| and its contacts 92 and 93 would have been opened to disablethe subsequent operation of relays I00 and H0. Contacts 94 would have been closed to complete a circuit for the operation of recording relay I" and lamp I32 would have been operated to indicate that the call originated at station I I-.

Relays 60, I0, and 80 are slow-to-operate relays with a preferred intervalv of about 200 milliseconds between energization and operation. Relays 40 and are slow-to-release relays with a preferred interval of about 300 milliseconds between deenergization and restoration.

While voltage divider networks could have been included at all of the subscribers stations, the interests of economy may be served by eliminating the network from one of the stations without in-. terfering with the operation of the system. There is no voltage divider network at station I0. Consequently, if a call originates at this station marking relay 35 will not be operated nor will registering relays 90, I00, and H0. However, at the time relay 50 releasesrecording relay I20 will be operated through the following circuit: ground, contacts 42, 33, 52, 95, I04, H3, relay I20, and battery to ground. The operation of lamp I22 will then indicate that the call originated at station I0. An overload relay'38 is provided for protective purposes. In the event of an overload through the circuit including marking relay 35 such as might be provided by faulty lines relay 38 will operate and close its contacts 39 to complete a circuit for the operation of a warning bell 59. The closing of contacts 39 will also complete a circuit for the operation of relay I60. i The operation of relay I may be utilized (by a circuit not shown) to transfer operations to manual control for identification on such faulty lines in any well-known manner.

While only a four party line is shown, it is obvious that additional parties could be accommodated by an enlargement of the application of the principles already disclosed in this specification.

While the preceding description has reference to a single embodiment of the invention, this should not be construed to limit the scope of the invention other than as necessitated by the appended claims.

I claim as my invention:

1. In a telephone system, a two-conductor line having at least two subscribers stations, means for connecting one of said Stations to said line, a network including a non-linear element at at least twoof said stations, said networks being ad justed to allow said non-linear elements to conduct, each at a difierent applied voltage, a source of current supplying different voltage of unvarying polarity which will render said non-linear elements conductive, means for applying said voltages sequentially to'said line beginning with the lowest voltage, 'means for indicating which one of the non-linear element is connected to said line, and means operated responsive to the passage of current through one of said non-linear elements for operating said last mentioned means.

2. In a telephone system, a two-conductor line having at least two subscribers stations, means for connecting one of said stations to said line, a network including a gaseous discharge tube at at least two of said stations, sources of voltage of unvarying polarity which when applied to said lines will render said gaseous discharge tubes conducting, said networks being adjusted to allow said gaseous discharge tubes to conduct, each at a different applied voltage, means for applying said voltages sequentially to said line beginning with a low voltage, means for indicating which gaseous discharge tube is connected to said line and means operated responsive to the possage oficurrent through one of said gaseous discharge tubes for operating said last mentioned means.

3. In atelephone system, a two-conductor line having a plurality of subscribers stations, means for connecting one of said stations to said line, a networkincluding a gaseous discharge tube at all.

except one of said stations, a source of a plurality ofvoltages of unvarying polarity, said networks being adjusted to allow said tubes to conduct upon application of different voltages, means for applying said plurality of voltages sequentially to said line at increasing voltage levels, and means for indicating the voltage level which rendered one of said tubes conducting, andmeans for indicating that the station without a. network is connected to said line, upon failure of all of the said gaseous discharge tubes to conduct.

4. In a telephone system, a two-conductor line having a plurality of subscribers stations, means for connecting one of said stations to said line, a network including a gaseous discharge tube at all except one of said stations, a source of a plurality of voltages of unvarying polarity, said networks being adjusted to allow each gaseous discharge tube to conduct at a different applied potential, means for applying said plurality of voltages sequentially to said line, and means including a marking relay for indicating the applied voltage which rendered one ofv said tubes conducting, and

,for indicating the connection of the station without a network.

5. In a telephone system, a two-conductor line having a plurality of subscribers stations, means for connecting one of said stations to said line, a voltage divider network at at least two of said subscribers stations, each of said voltage divider networks comprising a gaseous discharge tube and resistance in parallel, said tube and resistance combinations being adjusted to enable said tubes to conduct each at a different voltage level, a source of voltages at said levels which will render said tubes conducting, all said voltages being of constant polarity, means for applying said voltages sequentially to said line, means to indicate which gaseous discharge tube is connected to said line and means operated responsive to the passage of current through one of said gaseous discharge tubes for operating said last mentioned means.

6. In a telephone system, a two-conductor line having a plurality of subscribers stations, means for connecting one of said stations to said line, a voltage divider network at each subscribers station, each of said voltage divider networks com-- prising a gaseous discharge tube and resistance in parallel, said tube and resistance combinations be-' ing adjusted to enable said tubes to conduct each at a different voltage level, a source of voltages at said levels which will render said tubes conducting, all said voltages being of constant polarity, a marking relay responsive to current flow through any one of said tubes, a circuit connecting said marking relay to said line, means for including said voltages sequentially in said circuit in the order of increasing potential, and means responsive to the operation of said marking relay for indicating which of said tubes is connected to said line.

'7. In a telephone system, a two-conductor line having a plurality of subscribers stations, means for-connecting one of said stations to said line, a voltage divider network at at least two of said subscribers stations, each of said voltage divider netwonrm comprising a gaseous: discharge tube and resistance in: parallel;-. sources: of voltage; of unvarying polarity; .saida tub e and' resistance: com binations bein adjusted to enable said tubes; to conduct; each= tube: conducting; uponz application of a. particular voltage; said? particular voltage." being difl'erent for: each tube,,a marking: relay operablein: response: tocurrent flow! throughr. any-- one of said. tubes; a circuit connecting: said marking relay to.- said." line,' means.- for including v saidi voltages in said? circuit: in the order: of" in-- creasing. potential, and a-lseries of registering; relaysresponsive'a to the operation Ofi said. marking 1 relay] for. indicating: which of. said; tubes is'..connecteditovsaidilineh 8';- In: a telephone-system; aa two": conductor line.- having a. plurality of: subscribers! stations. means for connecting: one: of saidtastationsz to.) saidiline}; a voltage divider network at I all 1 except. one of said? subscribers. stations, eachwof saidivoltagei'divider networks comprising a gaseous? discharge: tube.- and resistance in; parallel; sources of? voltage at potentialswhichr will render: saidi tubes respec:- tively conductive. said tube; andv resistance combinationsibeing adjusted to;be:conductive:for. dii 25.

ferent't applied: voltages; a: marking: relayx oper=- able: in response? to) current flow through any of: said tubes, a circuit: connecting;saidfmarkingirelay to saidzline; airelay: controlled 2 test cycle! for including:saidivo'ltagesz inzsaid circuit: in the. orden of increasing; potential, and: for testing; the station inothaving; theinetworlc included: therein; a series of registering relays operatedzirr'accord ance with I theioperatiomo'r. 'nonoperation of. said marking f relay for'indicatin'g: which o'fr saidi stations is.- connected to said line, and: indicator? means controlled byrsaid registering'relayst 9; 1112a telephones system;aitwoeconductorr line having-"a plurality!ofrsubscribers: stations, means.

for" connecting: one: of r said. stations; to :said; line; 40

aevoltagedividerrnetworlc at za'lllexcept'fone of :said' subscribersi stations, .eGICIIZOf saidizvoltage dividerP networks.comprising a'gaseouszdischarge tube and a: resistance. connected; in 1 parallel; sources: of I voltagesxofiunvarying polarity; said' tube andcresistance: combinations-being adjusted iin valuezto respondvtooazrangewof l voltage stepssatiea'chr one OfIWhlOhiOIlG of :said tubesizwilli begin to":'conduct 1 thereby-short circuitingeits-iassociated resistance; meansaforsapplyingesaid voltages stepwiseto said:- line, recording means, andimeans': including? a markingrelayzforactuatingsaidzrecording means to: identifya'the subscriberfscstation 'at which the 2 tubesbecametconductingupon the? application of the: voltage: tor'whichrthat lstation wasradjustd; and means dependentiupon; the nonoperation nofd the emarkmga relay-to: indicate through" said irecording: means that theistationiwithout 'anetworkn isiconnectedztoithealiner.

10." InJa telephonesystemy ai'twoeconductorlima having: a plurality of subscribers stations; a'-r vo1tage :d-ivider; network at 1 each 'of :said subscrib ers", stations each of' saidnvolta'ge divider' networks comprisingsa: resistance" and gaseous: discharge: tube iconnecteduin'parallel, .sourceszofi voltage of unva-ryinggpolarity;thearvalueseorisaidiresistances andzgaseous discharge tubes :2 being: adjusted 1 to' enabler said gaseous:;-discharge'=tubesato: conduct when; a: particular Voltage: is applied"? to their parallel resistances thereby short circui-tingrsaidr resistances,;-thedivider networkszbeingi adjusted to; 4 enable 1 their. gaseousrdisoharge: tubes to be; conductive;- to: predetermined-v values: of: voltage; 1 eachmetwork being responsive to a different volt agecvaiuentaolinelrelayc az-zcircuit zconnectingisaid'z line: relay'tor each subscribers station throughsaid divider: network atv said station; said line relay being operable'when' said circuit-iscompleted; a-

slow-release relay operated by said line relay, a testing cyclecomprising aplur'ality of-sequentially operated relays, and' a circuit connecting said sources of voltage through contacts; of said sequentially operating relays: to said line, the volt-' having, a plurality' of subscribers stations, means forrconn'ecting one ofsaid' stations to said line including a subscribers switch hook, a voltage divider-network at all except one of said subscribers stations; each of said voltage divider networks comprising; a gaseous discharge tube and a resistance connectedin parallel therewith; sources-of: voltage of 'unvarying polarity, said tube and resistance combinations being soadjusted that each network is responsive to a different appliedxvoltage; a line relay-operated by the lifting. on one of said-subscribers" switch hooks, a slow-release relay. operated in response to operation ofisaidrline relay,- a-plurality of-sequentially operatingprelay'soperated in responseto operation of said slow-release relay, a circuit connecting saidvoltage sourcesto. said line throughcontacts of said sequentially; operatingrelays whereby operation of.said'relays-changes'the voltage appliedto said line stepwisaua' marking relay in the circuit connecting the voltages source to said line; said-markingzrelay operating only when the current passing; therethrough has reached apar ticular; level due'tothe-conducting-of one of said neon lamps and consequent short circuiting of its parallel resistance, a'seriesofregistering-relays equal in number tosaid voltage dividers, a registering relay. circuit connecting: said registeringrelaysthrough contacts ofsaid sequentially: operating-relays and said marking relay, each of said registering relays having contacts which, upon energization of said relay, disable the operation of (succeeding registeringrelays, one of said registeringrelays being operated when saidmarklng relay. operates/coincidentally with one of saidsequentia-lly operating. relays, and means responsive. to said registering relays for determining which of said gaseous discharge tubes is connected to. said line during the stepwise application of said voltages to said line, and means for registering...the connection of the station without a network when none of the network stations has caused the operation of the marking relay;

LEN" B; MITCHELL.

REFERENCE-S CITED The'following references are of record in the file of'this'patent'z' UNITED STATES PATENTS Number Name Date 663,747 Bascom Mar. 27,- 1928 1,857,827 Stacy"; May 10, 1932 2,'306;173; Logan t Dec: 22,1942 

